Television has become the world's predominant communications medium. The variety of programming available to the average television viewer has mushroomed in recent years with the growth of cable and satellite networks. It is now possible for a typical viewer to receive 100 channels or more in his home, including news, serials, movies, educational and other programming of almost every type.
Despite the variety of programming available, one of the drawbacks to television, from the viewer's perspective, is the fact that programs are broadcast on a common medium, i.e., programs are presented at fixed times to a large number of viewers. Not all users will find the scheduled time of a particular program of interest to be convenient. In the early days of television, it became common for many viewers to arrange their personal schedules in conformity with the television schedule, so as to be home and otherwise unoccupied when a favorite program was being broadcast. Since that time, it has become possible to record a favorite television program on a video recording device under the control of the viewer. Relatively inexpensive personal use video cassette recorders (VCRs) using magnetic tape cassettes have been available for this purpose for at least 20 years, and more recently other forms of personal video recording devices, such as recording devices using digital versatile disks (DVDs) or rotating magnetic hard disk drives, have become available.
Although personal video recording devices are generally available, may viewers find it cumbersome to pre-program these devices to record their favorite programs. For example, the viewer may be required to consult a television listing schedule (which is subject to change) to find the time and channel of the program in advance, and to program the device (using an interface which is often less than easy to use). Either out of habit, or because of the difficulty of programming, many viewers either simply watch whatever is being broadcast at a particular time, or arrange their own schedules in accordance with the broadcast schedule.
In order to improve the interface and make it easier for viewers to record their favorite programs, some broadcasters provide additional information and recording services to assist the viewer. An example of such a service is the TIVO™ service. When using such a service, an electronically encoded version of a television schedule is distributed to the viewer. The schedule contains electronic entries with respect to each of various programs. The entry may contain information such as show start time and length, channel, title, episode number, episode title, debut data, description, rating, etc. A recording device is often, although not necessarily, provided with the service.
The electronically encoded scheduling information can be used by the view to select programs for recording. In a simple implementation, the viewer may select a single instance of a scheduled program for recording, and the recording device will record whatever is broadcast on the channel and at the time specified in the scheduling entry. Some services offer more sophisticated recording options to the viewer. For example, if a viewer has a favorite serial program, the viewer may select all programs having a particular title for recording. Using such a feature, the recording device will automatically find all instances of such a program, without requiring the user to specify each such instance individually.
Where the user elects to record all instances of a serial program, there is a possibility that multiple versions of the same episode will be recorded. As is well known, it is common for the same episode to be broadcast on different channels, or to be re-broadcast on the same channel at a different time. In at least one such service, it is possible to specify that the recording device record only those episodes which have not been previously recorded. When this option is specified, the recording device compares the episode title and/or episode number of a scheduled program (from the electronically encoded scheduling information) with those episodes already recorded, and if the episode has already been recorded during some pre-defined interval, then it will not be recorded again.
Unfortunately, the electronically encoded scheduling data often does not contain a complete description of a program entry, and in particular may contain only a generic title of the serial program, without an episode title, episode number, or other information from which the particular episode can be identified. In these instances, the recording device can not determine whether a particular instance of the program has already been recorded, and so it will generally record the program instance. Because many serial programs are broadcast and re-broadcast multiple times, the recording device can consume significant storage space re-recording episodes which have already been recorded. Although it is possible for the viewer to manually delete duplicate episodes, manual deletion imposes additional burdens on the viewer.
In these instances and others, it would be desirable to provide an automated technique for determining whether a particular instance of a television program has been previously recorded by a video recording device under control of the viewer, and automatically taking some action with respect to recording a program according to the determination made.